Decree-Law No. 301/91 establishing the rules governing the national catalogue of varieties of agricultural species and the national catalogue of horticultural species and rules for their certification and marketing.

The Decree-Law stipulates that only distinct, homogeneous varieties, whose agricultural and utilization value is satisfactory, may be entered into the National Catalogue of Varieties. Only listed varieties may be marketed, while authorization to import and market varieties earmarked for export and import varieties for scientific research may be obtained. The National Centre for the Protection of Agricultural Production coordinates regional services for production control and certification, prescribes the conditions and methods of registration and cataloguing of varieties, etc.